Could we fly a bizjet into a remote strip in the Himalayas?

The weather itself presented another challenge. Though the airport would open at dawn, at that time of year it was usable only until about 10 in the morning, when the valley winds would begin howling up around the ridgelines. Each morning, our crew would have about a three-hour window to arrive and depart. We’d also learned Bhutan’s monsoon season was about to begin, so each passing day lessened the likelihood that we’d pull this off.

In the meantime, our customers were hurriedly finalizing their production schedule. Paro would be the center in a long line of dominoes. As we would be hopscotching the customer around the world, the most likely scenario would be that we’d land there just fine but be unable to depart the next day, thereby wrecking their fine-tuned plans. Fickle Himalayan weather guaranteed there’d be no sure way to know what was in store until we arrived.

While I continued designing elegant curves that fit the airplane’s performance within those nasty-looking terrain contours, Atterbury set off on a couple of road trips.

He and Weeks had contacted Bhutan’s national airline, Drukair, to glean insight from their counterparts on the other side of the world. Insights such as: We had literally been attacking this problem from the wrong direction. After flying in the jumpseat of a Drukair jet, Atterbury made an important observation. Just looking at maps, the obvious path out of Paro appeared to be southeast but without the dreaded Whifferdill. But when he stood on the runway, it became obvious they were better off going in the opposite direction—which pointed straight at the mountains. It was, in fact, Drukair’s preferred departure and a valuable illustration of the need for an experienced crew member on site.

From where I sat, it looked nuts: The crew would immediately have to bank right, pointing the nose at an imposing mountain, then honk it through a 270-degree climbing turn inside a box canyon to come out above the ridge and head back over the runway. On the plus side, from the runway, they’d be able to see everything inside the turning area. Nothing was hidden, which made it the best choice.

With three weeks to go, we still had to train our crew, chart the procedure, identify obstacles, develop weight and speed tables, and arrange for a Bhutanese safety pilot to ride shotgun. I paid for the custom charts and flight simulators on my company credit card, and our crew shipped off for Manchester, England, which had the only visual model of Paro in the Western Hemisphere.

Back home, I was still crunching numbers and seeing that valley in my sleep. It’s not enough to determine a crew’s ability to fly a given procedure. We also have to figure out how much of the runway they’ll use, flap settings, and critical speeds—all based, of course, on losing an engine—to arrive at the crucial number: How heavy can that airplane actually be?

The answer was “not very,” which introduced another limitation: Less weight equals less fuel equals less range. It could be a clear day in Bhutan, but if there were no usable airports within range, they’d be just as stuck.

As the departure date loomed, all those uncontrollable factors weighed heavily on us. As each day went by, we scrutinized conditions closely, repeatedly calculating winds and their effect on fuel consumption. Finally, the day arrived.

It didn’t help that all the critical events would happen when it was the middle of the night in the States. I went to bed that evening, anxious but hopeful, knowing that our dispatchers were keeping a close eye on every detail.